Pre-transplant downstaging strategies for hepatocellular carcinoma with portal vein tumor thrombus: Current therapies and future challenges

Table 1 Comparative classification of portal vein tumor thrombus and clinical implications

System	Grade/type	Anatomical extent	Typical characteristics	Downstaging feasibility
LCSGJ	Vp0	No portal vein invasion	Normal portal flow	Not applicable
	Vp1	Thrombus distal to second-order branches	Peripheral PVTT; limited hepatic impact	High: TACE, TARE, PBT often effective
	Vp2	Thrombus in second-order (segmental) branches	Segmental invasion; localized disease	Moderate to high
	Vp3	Thrombus in first-order (right/Left) portal vein	Major branch occlusion; moderate liver function compromise	Moderate: Requires combination approaches
	Vp4	Thrombus in main trunk or contralateral portal vein	Central occlusion; severe portal hypertension	Low: Systemic + radiation or experimental
Cheng	Type I	Segmental branches of the portal vein	Equivalent to Vp1-Vp2; good prognosis if treated early	High
	Type II	Right or left portal vein	Similar to Vp3; higher recurrence risk post resection	Moderate
	Type III	Main portal vein trunk	Equivalent to Vp4; marked hemodynamic impairment	Low
	Type IV	Extending into superior mesenteric vein	Extensive systemic vascular involvement	Very low: Limited to palliative/systemic care

LCSGJ: The Liver Cancer Study Group of Japan; TACE: Transarterial chemoembolization; TARE: Transarterial radioembolization; PVTT: Portal vein tumor thrombus; PBT: Proton beam therapy.